Pagoda SL Group
W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: Tomnistuff on June 15, 2019, 13:02:05
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When the linkage is NOT connected to the injection pump, is it normal for the IP control lever not to return to its STOP when released? Or is this indicative of some other problem (something hanging up inside the IP maybe)? Mine hangs up at about half lever open position. I added a weak supplemental spring to the linkage system temporarily. The pump was rebuilt by Pacific during the engine rebuild by Metric.
Tom Kizer
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The linkage lever has a light coil return spring. It should automatically return to stop when disconnected.
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Hi Tom, I think Joe is referring to the spring in this picture which returns the IP lever ('linkage arm') to its stop.
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I recall that my IP lever is lazy but for the most part returns to the stop with the spring. It should not bind anywhere along its travels. If it has a catch or binds at some point, I would think that could be an issue.
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Thanks, gentlemen. Mine definitely drags on return. I can't say it's severe, but it will never return to its stop without help. I added another spring to the system to drag it back to the stop by pulling the control rod upward, in spite of all the other springs in the system helping the throttle to close. If I remember correctly, there's the one on the firewall transfer shaft, one on the throttle body lever, and the one on the IP lever shaft. I added another to get the throttle to return when all is hooked up.
I don't know how the exact mechanism inside the IP works, but I suspect that something inside the pump is not returning, even when I pull the IP lever up with the control rod and all the springs. Could something inside the pump be staying at a high flow setting even when the lever is forced back to its stop?
I have an ungodly amount of fuel flowing into the engine, even at idle and at high engine speed even with the IP lever against its stop. I did the tests on the CSV. It's not leaking, it's not stuck, the solenoid is working great with 12V manually applied, and it's not getting 12V from the Thermo Time Switch (which isn't working apparently). The Cold Start Relay seems to work fine on a bench test. All the wires and connections are great.
I haven't touched the Barometric Compensater nor the Warm Running Device, so I guess they could be the problem. However, there is a lot of fuel coming from somewhere.
HERE'S WHY I KNOW. When I fired up the car for another split linkage test, it started instantly with the IP lever and throttle plate closed but ran roughly with lots of smoke. I didn't touch the IP but opened the throttle plate in an attempt to kill the smoke with just more air. The engine revved quickly to (believe it or not) 4,000 RPM+ before I could react, but the black smoke never stopped. I shut it down and decided to think it all through again.
My current desire is to eliminate any source of fuel that is not supposed to be there. I can't make it run well enough to do anything that takes more than a few seconds because I spend more time cleaning my four sets of plugs than anything else. I can't even get it to warm up completely.
I'm thinking I'm going to have to re-torque the head bolts before I get it warmed up for the first time, because yesterday, after running it for about 30 seconds, I checked the coolant level and proceeded to overflow the overflow bottle. I get the impression that the engine is behaving like it has blown a head gasket and exhaust gas is going into the cooling system. It may be that the smoke that I experience is not fuel (there's plenty of that too!), but it might be antifreeze that was pushed back into the cylinder after each 30 second run due to the exhaust gas-pressurized cooling system. On second thought, maybe this is the root problem. At any rate, it has to be done. I might as well do it next.
Now I've noticed that my oil pressure gauge has stopped working. It's stuck between 0 and 1 on the gauge and doesn't even respond when I add 2 bar pressure from a hand pump. Oh well, at least reproduction Pagoda oil pressure gauges are available in Belgium for a few hundred Euros.
Thanks for your help and sympathy.
Tom Kizer
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Maybe your injectors are stuck open (dirt etc.) ? Sounds like your coolant system needs burped. Keep toping coolant till air is burped from the engine. I have some good used original oil pressure gauges when the time comes (cheap). Also the thermo-time switch supplies neg. (ground) current to a relay which in turn provides + current to activate the CSV. I hate to see you in such distress. Keep plugging away.
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Tom,
Assuming you filled the pump with oil I am slightly concerned that the rack in the pump may be stuck from sitting. Perhaps Joe can chime in here as I don't know the early pumps that well but there are a couple ways to access the rack to check and see if it is moving.
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Thanks Joe and Shvegel.
I'm off to church now but I'll try to think this out and get back to you this afternoon. I know I need to understand the cold start devices better. I ordered a new oil pressure gauge, but now Paypal has the payment pending for some unknown reason. I'm about ready to cancel Paypal. They are nothing but a problem too often. I'm ready to start using a prepaid credit card to limit risk for internet purchases.
Tom Kizer
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Good possibility from Pat, could be a stuck rack in the IP causing the rich mixture.
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As much as it breaks me into a cold sweat to think about the rack being stuck due to inactivity after rebuild, it at least fits the history of my restoration. Two of the first things done were to ship the engine to Metric Motors and the Injection Pump to Fairchild Industries in Sept, 2011.(I previously said "Pacific Fuel Injection" by error). For the next 6 years it sat in a box, in a heated garage wrapped in plastic. For 2 more years it sat on the side of the engine with only the oil that Fairchild left in it when they shipped it back to me. I spent those 8 years reassembling and restoring the rest of the car alone in my spare time.
So be it. Now I have to live with the consequences. It looks like I'll have to remove the IP whether it's installed out of phase or not. Can I access the rack by removing the screw at the center of the attached photo to see if it is free, temporarily stuck or completely seized?
Thanks for all the heavy analysis you've done so far.
Tom Kizer
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No need to remove the IP yet. Remove the 10mm hex bolt and cover. Thread a metric machine screw into the end of the rack and see if you can move it back and fourth.
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Not to get side tracked...but when did they switch from the bolt to the rubber cap for the rack access?
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Probably 280 SL's had the rubber cap.
I've seen this problem on a number of cars where the IP lever was sticky or it seemed to be catching inside the pump. You can increase the throttle linkage return pressure by selecting a hole further away from where the return spring is located. I think there are three different positions and each one will produce more return pressure as you move the ends of the return spring further apart.
I've preferred the close setting on the cars we've worked on so that the gas pedal felt lighter but sometimes that wouldn't be enough and more tension was required.
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No need to remove the IP yet. Remove the 10mm hex bolt and cover. Thread a metric machine screw into the end of the rack and see if you can move it back and fourth.
Thanks, Joe, for the sage advice.
I wanted to post my reply a few minutes ago and in looking something up on another site, I erased my very carefully composed test report with photos, observations and conclusions. Since we have dinner guests arriving in a few minutes for an early dinner, I'll probably have to rewrite it tonight or tomorrow morning. I'm going to suggest to the moderators that we build in an automatic "DRAFT" save function that automatically erases the draft when the posting is made. Until then, I'll start typing all my posts in Word and pasting them to our site when finished.
Anyway, my rack is reasonably free, if just a little "draggy" which we can discuss after my post tomorrow.
Tom Kizer
Here's a teaser, and why it took so long for me to be able to even recognize what the rack is doing relative to the throttle lever. Did you all know that our IP has in it mechanical systems that take advantage of some of French Mathematician René Thom's "Théorie Catastrophe" concepts?
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Sorry Tom, I am not familiar with Rene or his concepts. I am familiar with a catastrophe from time to time :)
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Good Afternoon
I know this is way too long but describing everything that happened without understanding it is really difficult. Even my observations probably are wrong or have a simple explanation.
I’ll try to remember all of my observations and conclusions when I examined the rack on my pump.
When I removed the bolt in the photo that I posted above in reply #9 a few days ago, I was surprised to find it wasn’t a bolt but a threaded cap with a hex, which, of course, you all knew. Probably expensive to make, which I suppose is why they eventually changed it to a rubber plug. My pump is a PES 6KL70/120RL11 in a late 1966 Italian version 230SL manual transmission car.
I also discovered that the threaded hole in my rack is not an M4, but probably an M5. An M4 screw worked by just side loading it a little.
When I removed the cap, the end of the rack was flush with the end of the threaded tube within which it slides and onto which the cap screws. That rack position is shown in photo #1.
From that position, when I pulled on the screw, the rack pulled out about 5 or 6 mm, but was stopped by something internal to the pump. That position is shown in the photo #2. That protrusion distance agrees with the design of the screw-on cap, which provides just about that much space for the rack to protrude from the tube within which it slides. As I pulled out the rack with the screw, I could feel resistance of two types. The pull out effort was resisted by the progressive feel of a light spring as well as a light smooth and constant resistance that felt like a slip fit with a thick lubricant. A few months ago, I filled the injection pump with Castrol GTX 10W30 engine oil before ever turning over the engine. NOTE: I used Castrol GTX 10W40 for the engine initial fill and for priming the engine. My pump oil supply is self-contained and separate from the engine. I was afraid the 10W40 engine oil would be too heavy for the injection pump. When I released the tension on the screw, the rack returned to its initial position smoothly by the force of the spring(s) that resisted its forward movement.(photo #1).
Once again, from the initial rack position, I inserted the screw and pushed the rack farther into the IP housing. And again, I could feel the “drag” of a heavily lubricated slip fit of the rack in its hole as well as the progressive resistance of a spring. The rearward travel of the rack from photo #1 position was limited internally to about 12 or 13 mm. This position is shown in photo #3. It was obvious to me that the normal (for the moment) position of the rack is with its end flush with the tube within which it slides, and that that any movement from that position is resisted by spring(s). When the rearward force on the screw was released, the rack moved smoothly back to its photo #1 position by the force of the spring(s) that resisted its rearward movement.
Thus far, all rack movements were initiated manually by the use of the machine screw. Since none of the previous rack movements had any effect on the IP throttle lever, I checked to evaluate the effect of the IP throttle lever movements on the rack movements, if any.
With the rack in photo #1 position (apparently the normal, for the moment, position), when I opened the IP throttle lever (without any linkage connected) from its closed throttle stop position to its Wide Open Throttle position, the rack moved smoothly and continuously from the photo #1 position to about one mm short of the photo #2 position. Without releasing the IP throttle lever, and with the use of the screw, it was possible to pull the rack that extra millimeter farther forward to the photo #2 position. But when the screw was released, the spring forced it back to the photo #2 minus 1 mm position achieved with the IP throttle lever.
NOTE: No relationship test is valid without evaluating the relationship forward and backwards, so I continued the backward test.
When I smoothly and slowly allowed the IP throttle lever to return from its Wide Open Throttle position to its closed throttle position, the IP throttle lever, driven by the torque of a return spring, moved relatively smoothly back to ½ throttle where it hung up, as I have discussed in a previous post. Strangely, to me, the rack did not follow the movement, but remained at the photo #2 minus 1 mm position. Everything was hung up at that condition. When I exerted enough return spring type force to un-stick the IP throttle lever, I was able to move it relatively smoothly back to a ¼ throttle position, but the rack position did not change. It still stayed at the photo #2 minus 1 mm position. When I exerted slightly more closing effort to the IP throttle lever, it “draggingly” returned to its closed throttle position against its closed throttle stop. Amazingly, to me, during that last ¼ throttle movement of the IP throttle lever, it “dragged” the rack from the photo #2 minus 1 mm position all the way back to the photo #1 position. This is the series of movements that describe the relationship that, in my previous post, I referred to as French Mathematician René Thom’s Catastrophe Theory (in English, this time). I have included a graph that describes the discontinuous function of the IP Throttle Lever/IP Rack relationship. The graph is 100% IP throttle lever travel large and approximately 100% rack position tall. The fact that it can be called a catastrophe theory type graph is not important. The important thing is that the behavior is difficult to understand in that it behaves differently going up than coming down. I assume that the entire lower two thirds of the graph is controlled to some extent by the Barometric Compensator, the notched screw on the back of the IP and the Warm Running Device (assuming what is shown about the rack is what it is supposed to be). Maybe the whole relationship is shifted up or down by those devices. My purpose here is to describe something that I don’t understand so completely that those of you who know how these pumps work can see what might be wrong, if there is something wrong.
Anyway, I hope what is here helps you to help me. I’m completely baffled as to where the fuel is coming from – if it’s fuel and not antifreeze as I mentioned a couple of days ago. I'm hoping you can see the problem and it's just that I haven't yet adjusted the WRD and BC yet, because I have not yet found a leak among the other Cold Start Devices.
Thanks for any insights you might provide.
Tom Kizer
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I have a car very similar to yours except it has a 250SE engine. Even the pump on my car doesn't have a second solenoid on it which kind of makes me wonder if you have the right pump on your engine. I've seen this before but your pump number sounds right so I'm not sure what to think.
If it doesn't work right send it back to the builder. The warranty is probably long expired but he may still be willing to look at it for you. One thing I wouldn't do is try to fix it myself. Unless you understand how something works it's nearly impossible to do that. There's something wrong with that thing.
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I am just doing throttle linkages on my can and I am wondering if you have both return springs on? Firewall spring is quite a bit heavier than the throttle body one.
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Shvegel and Dan
Yes, both my springs are connected, although the one on the firewall is in the second hole. With my lighter weight supplemental spring on the transverse shaft second lever, it behaves perfectly with the throttle damper. With the firewall spring in the front hole, it's really too heavy on the throttle, even with the supplemental spring removed.
Dan, I'm curious regarding your experience and others' as well regarding the "state" of rebuilt pumps when they are received back from the rebuilder/flow bench calibrator.
Do they tend to set what they think is a "middle-of-the-road" flow calibration flow bench spec sheet or do they just set up the pump to make sure it's working smoothly and let the owner or restorer take care of the tuning after he or she puts it back on the engine? It's almost as if mine is set at the "rich" end of the scale on everything. Example, how many shims of the various types would the rebuilder install assuming the pump had none when he received it from the client. Where would he tend to set the adjustment screws? Do rebuilders have a "baseline" calibration to which they set all newly rebuilt pumps before shipping?
When I was setting up 1, 2, and 4 barrel carburetors on Ford's Carburetor Laboratory flow benches in the early 1970's in Dearborn, Michigan, we had, for the prototype cars we built, a standard calibration flow bench setup spec sheet for each carburetor. All that was necessary was to bolt it on the engine and "maybe" do a final "tweak" after the first emission test, driveability test or performance test.
Every carburetor from the laboratory at least worked, and not too badly to drive pretty well.
I think these things would be nice for the user/owner to know about our injection pumps. To Mercedes, everything seems to be a big secret, even on 50 year old cars.
Tom Kizer
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Pumps are set at various RPM’s and loads based on a specification sheet for each pump/governor combination. The Barometric/warm up regulator(they work together like a teeter totter.) is also checked and adjusted. You should only need to set idle mixture.
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Pumps are set at various RPM’s and loads based on a specification sheet for each pump/governor combination. The Barometric/warm up regulator(they work together like a teeter totter.) is also checked and adjusted. You should only need to set idle mixture.
I would agree in general. I have had to adjust the fuel mixture by turning the barometric compensator in or out a small amount but most of the time they're set OK. I never touch the screws inside the back of the pump but I will turn the idle mixture screw as required to obtain a solid idle speed.
I think a bit of this discrepancy in results is due to engine wear and how much compression you have. I imagine that pump rebuilders set hem up to work well with a fresh engine because that's the time to get your pump looked at. Most pumps tend to go rich over time and you sure don't want to run a fresh engine on the rich side.
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Thanks Shvegel and Dan,
I guess I've been lazy by trying to do it the easy way, by running tests, playing detective and seeking someone with lots of knowledge and experience to whom it has happened before. You all have been a big help, but if I am to be finished in time for Meeting of the Clans II, I need to stop harassing you guys and find out what's really happening in this engine by turning some wrenches.
I'll start by calling Robert Fairchild of Jerry Fairchild Industries. You are right that the warranty is long expired, but I'll just ask his advice, since he rebuilt it years before I installed it. It's probably gummed up inside or something got knocked loose.
Apparently it's not coolant because coolant is supposed to burn white. Oil burns blue, and fuel burns black. That tells me it's fuel so I need to find out where it's coming from. Possibilities are WRD, BC, Idle adjustment screw, Pump rack hang-up (known) and maybe even out of phase pump installation.
Joe A. mentioned to someone else that their richness, if a split linkage test showed that it continued at high speed, could be due to the BC. Mine does. I discovered it when my split linkage test went awry and I revved it to 4,000+ by accident with lots of black smoke.
Anyway, tomorrow I start. I'll keep you all posted.
Tom Kizer
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Wow! I expected to work at least one or two days before I found something strange and unexpected.
Step #1 was to remove the Barometric Compensator, count and measure the shims and try to determine if it's still functioning. I didn't get far.
The first thing I found is that there are six shims. The first four nearest the base of the hex of the BC housing are 0.0215", 0.0225", 0.0215" and 0.0210". The two nearest the IP threaded hole and the last two installed were 0.0800" and 0.0775". So it had a total of almost 1/4" of shims (0.2440"). The shims took up almost half of the BC threads.
I measured the distance from the tip of the pin to the base of the hex,without the shims and found it to be 21.3 mm. The Technical Manual says a good BC should be approximately 21 mm and a bad one approximately 25 mm. So apparently, by that standard, I have a good one.
Then I put the BC in a fruit jar, punched a hole in the lid and put a suction cup attachment on my MITYVAC. The BC pin responds really well to vacuum, extending an additionnal three or four millimeters in 15 in. hg. vacuum. That's not a specification, but I just wanted to know if it worked or leaked. It works. It doesn't leak.
I'm so sick of black smoke during warm-up, I'm going to remove all the shims and reinstall it to at least see if I can cause a lean running problem. If yes, I'll start putting shims back on using the technique of "artillery ranging".
Wish me luck.
Tom Kizer
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The further out the BC the richer it will run. Put all of your shims back in and put a piece of tape at the 6 o'clock position when it's tightened down. Remove your BC and remove one large shim and tighten it down. The position of your tape should be in a different place. A half turn generally results in a much leaner setting. A thick shim can give you a full turn.
If your engine starts but is running very slowly you are probably too lean. Replace the shim you just removed and try a thinner one or try turning you BC out until the engine idles smoothly and picks up RPM's quickly. Watch where your tape is positioned and try to find a combination of shims that will land right on the sweet spot of where your tape is sitting. It's really not that hard to do.
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Hi Dan,
That technique sounds like it will work quite well. My two thickest shims aren`t really shims at all, but thick machined washers from somewhere. I`ve had the car since 1987 and I did not install them.
Since the pitch on the BC thread is 1.5 mm, my thickest shim (2.02 mm) would equate to 484.8 degrees of rotation or 1 full turn plus 124.8 degrees. But, by repositioning the thinner shims with regard to the thicker ones, it`s possible to adjust the total shim thickness in increments averaging about 0.56 mm, which is increments of 134.5 degrees of rotation. And if I drink all the beer I have in cans, I can make lots and lots of 0.08 mm or 0.003 inch thick shims.
I`m too impatient to make adjustments in small increments, so I`ll still use the artillery ranging method. I`ll just have to take copious notes from the split linkage test with each shim change.
The reason this email has been so long coming is because just when I discovered the Barometric Compensator Shim quantity and thickness, I also discovered that my 30+ year-old battery charger, even though it was making noise, was not making amperes. I wanted to try a test with thick shims removed but my engine starter just said in response, "huh".
I`m about ready to start my shim testing, so I`ll go back to work.
Tom Kizer
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Good spotting. I wonder if somehow they tried an odd way of setting the pump up and forgot to take them out. I have never heard of anywhere close to that many shims.
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Tom, McMaster Carr has various metric shim thicknesses for little money. I think I use the 14mm I.D. round shims.
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There appears to be light at the end of the tunnel. My original thread was "New engine startup - NOT", but I got hustled over to a new thread (this one) by the "dragging and sticking" of my IP throttle lever during a split linkage test and the need for a supplemental throttle linkage spring to fix it.
Anyway, having finally discovered the Barometric Compensator shim problem, I started trying to set up a test program to get the car running and get things done in preparation for Meeting of the Clans II, with the help of many of you. My last few days have involved buying a new battery, hold-down rods and battery charger. It seemed that every time I fixed a problem, I turned my back and another problem bit me in the butt.
Today I ran some shim removal iterations.
First test:
I removed the thickest two shims (0.0795 inch and 0.0770 inch), leaving 4 shims totaling 0.0850 inches. By the way, since I'm using a digital caliper, the last digit keeps changing by 0.001 or 0.002 inches. Results: It started immediately and ran up to about 2,000 RPM. With the split linkage test, air made it run lots faster but fuel almost caused it to stall, so it was still rich.
I shut it off immediately but was very happy to see there was no smoke in the garage and the running was very smooth.
Second test:
I removed another shim (0.0225 inches) leaving three shims totaling 0.0625 inches. Results: It didn't want to start until I reduced the idle air flow from when I had raised it a few days ago due to the smoke filled garage. It then started immediately and ran cleanly up to 1750 RPM. Vacuum was 16 In. Hg. The split linkage test crudely said it was pretty well balanced although really fast. More air brought the speed down and more fuel brought the speed down also. Again, NO SMOKE and RUNNING SMOOTHLY, but still way too fast. In accordance with Joe Alexander's advice, I burped the cooling system with the top radiator hose. It burped once then drank lots of coolant from the overflow tank. Eventually that problem will go away too.
Again, I was very happy. It's still running too fast to worry about small changes like the IP idle mixture screw so I'll take out another shim tomorrow, and reduce the idle air flow to try to maintain the fuel/air balance by Kentucky windage. Hopefully I can get the speed down to within the trimming range or until shim changes don't help. I'm still working only with the Barometric Compensator. I haven't touched anything else.
At least there is not more smoke in the garage and my plugs are staying clean. I'll check them tomorrow to see if they are cleaning up a little or if i should change them again.
The car is getting close to driveable finally.
By the way, I've blown three #6 fuses today, all during the first few seconds. Something isn't right with the cold start electrical circuit. At least it doesn't keep me from running the tests. I'll start diagnosing it when I've got the idle speed and fuel/air ratio under control.
I'm going to quit for the day. Goodnight. At least it's a holiday here tomorrow (St-Jean Baptiste)
Tom Kizer
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A new day and the 3rd thru 8th iteration of shim removal followed by two IP idle screw adjustments.
One at a time, I removed all the shims and the idle speed kept dropping with each shim removed and its corresponding idle air valve adjustment. The last shim removal resulted in an idle speed of 600 RPM and 16 in. Hg. Vacuum. The last shim removal dropped the speed from 1200 RPM to 600 RPM, so I couldn't really keep the last shim.
So I enriched the IP idle adjustment screw two notches, which resulted in 950 RPM and 15 -16 in. Hg. But both speed and vacuum were unstable. Leaning the screw one notch (still one notch richer than rebuild level) and rebalancing air and fuel with a split linkage test yielded: 950 RPM / 16 In. Hg. Vacuum, with all values very stable.
With new plugs, I followed up by verifying, with my timing light, the spark timing that I had set statically a few days ago. I'm running Premium fuel, so I'm not going to worry about the two extra degrees until the cause me a problem.
The value is 32 degrees BTC with no vacuum line.
Once it's warm it's quite good, but it's still blowing #6 fuse every time I start the car, so it's difficult to start cold, even on a nice day like today.
It's cold start devices electrical diagnosis time.
Thanks for all your help and advice for getting it running warm.
Tom Kizer
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Put your vacuum line back on and adjust timing to 38 - 40 degrees BTDC at or above 3,000 RPM. Removal of the vacuum line is only for testing.
Your vacuum reading sounds a bit low and should be more in the 18 - 20 inches range on a fresh engine which will be fixed by more ignition advance.
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Hi Dan,
I was afraid you would say that. I know you are right but I tend to get all puckered up when I rev an engine to high RPM's with no load, although I know it's not supposed to do any harm at 3,000 RPM. I'm also afraid of high voltage, so I'll have to adjust the distributor while in a state of anxiety. When I was a young fuel systems engineer at Ford, I used to regularly break the rules by looking down into a carburetor while the engine was running 6,000 RPM on a dynamometer. That's when I was immature but immortal. I stopped doing that when one day when while I was not in the test cell, one of my test engines failed a rod and an oil pan and set off the fire extinguisher system in the test cell.
First, as an excuse not to do what you say I have to do and to provide time to build courage, I'm going to try to discover why the circuit on fuse #6 is blowing fuses the instant I hit the starter, even though fuse #6 is not necessary to start the car. As far as I can see, it only fuses the heater blower, automatic starting aid and electromagnetic starting valve, which I think means heater blower, CSV and IP start solenoid. If I'm wrong please correct me. I'm confused by the multiple and varied naming of devices. I think the clue to the problem is in the fact that it's a 25 Amp fuse. What needs 25 Amps? It must be a secondary power draw or a short circuit to another power draw like the starter. Or some severely damaged relay or switch.
Anyway, I'll find it. And thanks, i think, for reminding me.
Tom Kizer
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Sorry, Dan and everyone else. I was wrong. I got overconfident.
I still haven`t found the reason why I`m blowing out #6 fuse every time I crank the engine. It's true that it's supposed to handle only the heater blower, the CSV and the IP Start Solenoid, but I went back and searched my 50 page Assembly Sequence document and found that I had connected a heavy wire to #6 circuit that feeds power to what I've called an Accessory Switched 12V Power Distribution Barrier Block. It's a small box full of places to access switched 12V to run little accessories like a backup camera, a front camera, a GPS power supply, heater and AC blower motor (note that the original heater motor and switch is no longer connected), and a vacuum cruise control "control circuit". Then I saw something really stupid. Downstream of the 25A fuse (#6), there's an in-line 30A fuse for the AC blower motor.
I still can't figure out what is happening because none of those things are turned on, so they are not drawing any power.
Anyway, until I started removing shims from the Barometric Compensator, none of my attempts to start the car brought me to notice that #6 fuse was blown. That's probably because until then, the IP, with the BC 6 shims, was so rich that non of the non-working cold start devices were even noticeable. Remember that all of my significant leaning out of the fuel system happened in the same day. The sequence was: Start the engine rich, try to keep it running to do a split linkage test, stop the engine, remove shim(s), restart the engine which is now warmer and still rich, do another split linkage test, stop the engine, etc., etc. By the time it was really idling nicely, it was also at running temperature and restarted instantly.
The next day, it took forever to start because: 1) it was room temperature (cold), 2) too lean to start easily without the cold start devices working.
When I noticed the blown #6 fuse and replaced it, the next time I cranked, I used the remote starter connected between the B+ and the "G" terminal on the TTS.
My ear was really close to the #6 fuse when it went "POP".
Now, here I am trying to find out why.
Since my 230SL is a manual transmission, my #3 fuse is connected to nothing. I wonder if I can reconnect that "Accessory Switched 12V Power Distribution Barrier Block" wire to #3 fuse, which is unused, with another 25A fuse and run the #6 fuse with only the CSV and IP Start Solenoid.
Any opinions? Right now, I'm a retired mechanical engineer drowning in an electrical engineering lake.
Suggestions? I'm looking for reasons why what's happening is happening, but I am also looking for solutions without purist prejudices.
Tom Kizer
PS: I've checked all the cold start devices except the WRD and the TTS hot resistance values but that's next. Everything else checks out perfectly including the wires from device to device and from the battery. The WRD doesn't draw power so that should have no effect. WRD requires coolant draining which I'm doing now.
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Only stick fuses where they're supposed to go. I would imagine that the wiring going to a 25 amp fuse would be considerably heavier than one going to an 8 amp fuse.
Look at anything that's not stock to your car. Electrical tape and cheesy wiring would be my suspects.
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I have a question about the TTS testing.
My test results compared to the Tech Manual objectives are:
Resistance terminal G to ground < 35 deg C should be about 20 Ohms and is 32.5 Ohms
Resistance terminal W to ground < 35 deg C should be 0 Ohms and is 0.6 Ohms
Resistance terminal G to ground > 35 deg C should be about 60 Ohms and is 64 Ohms
Resistance terminal W to ground > 35 deg C should be about 100 Ohms and is 130 Ohms.
Do these results sound within reason? Should I be concerned?
Also, In an attempt to lighten the load on my system, I'm looking at using an unused fuse circuit - #3 which I think is used only for auto transmission cars. Mine is wired to nothing. I upgraded my car to a 1.9HP starter, a 55 Amp alternator and a 280SL regulator. I hope I haven't screwed things up.
Tom Kizer
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Tom. If you have upgraded your alternator to 55 amps please please replace the 10 gauge wire going from the back of the alternator through to the starter post. The 10ga wire is only good for 30 amps. This is an achilles heel area of the electrical system. If your alternator ever full fields because of a dead battery or jump start then this wire can melt and potentially catch fire. Replace it with an 8ga or above.
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Hi Tyler S,
I really appreciate your post. It really shows that you care about others. It also prompted me to look at my previous posts to see what gage wire I used when I repaired damaged wire at the same time I changed the alternator. I found it by searching.
I had forgotten that you and I both participated in the same conversation in my old thread entitled, "Potential Repeat Disaster Prevented" in 2015.
I don't know how to post a link to this thread, but the title is above and I found it by searching, "starter wire".
Thanks again.
Tom Kizer
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Back in reply #4 of this thread, I mentioned that I noticed that my oil pressure gauge had stopped working. Actually, apparently when I discovered the problem, It had not worked since I took the car apart eight years ago. While waiting for a new oil pressure gauge to arrive, I pressure checked the metal line from the hose to the gauge. It was blocked or kinked. Nothing passed. I ordered a new one in a panic. Meeting of the Clans II is getting too close to wait.
While waiting for the line to arrive, the gauge arrived so I started to remove the instrument panel. I removed the line and spent a few "nothing else to do" hours trying to unplug it. I finally succeeded with Rust Remover, WD40 and finally galvanized wire from the hardware store. Apparently there was nothing wrong with the gauge, so I wasted a few hundred dollars and a week waiting.
At least that problem is fixed now and I've got 3 Bar pressure after a few seconds of cranking.
Regarding the cold start problem and the constantly blown #6 fuse, I rewired the underdash to take all the new stuff off of fuse #6 and put it on the unused circuit where fuse #3 would go. That means that the heater blower is also no longer on fuse #6, since my AC system is on fuse #3 along with the cameras, GPS power and cruise control.
After putting it all back together, I tried cranking again and instantly blew #6 fuse again, with nothing on that circuit except the wire to the cold start relay, the time switch, the cold start valve, the IP start solenoid and the famous thermo time switch.
With only one wire being fed by fuse #6, it still blew the fuse during about 2 seconds of crank.
Tomorrow has to be the big day.
Wish me luck.
Tom Kizer